This study is a prospective, single crossover, double-masked, controlled clinical trial that will use topical brinzolamide (Azopt)ophthalmic medication to try to improve the nystagmus and visual consequences of nystagmus in patients with infantile nystagmus syndrome (INS). Subjects will undergo a clinical exam, questionnaire and eye movement recordings on day 1 and then receive either topical Azopt or placebo three times a day in both eyes for days 2,3 and 4 followed on the morning of day 5 by a repeat clinical exam, questionnaire and eye movement recordings. After at least one week, this protocol is repeated with the crossover regimen being taken by the subject. One week after all medications are discontinued, another clinical exam is done before study discharge. The hypothesis is that nystagmus and associated visual symptoms will be improved while on the Azopt compared to the placebo. There will be a total of 5 visits over a 1-2 month period.